Giustino Borzacchiello

This plugin will show stats about your posts after your content.
Currently it shows:
<ul>
<li>Word count</li>
<li>Characters count</li>
<li>Reading time</li>
<li>Speaking time</li>
</ul>

Postats

This plugin gives some statistics about your posts (word count, etc.)

whiletrue

Reading Time shows the estimated reading time of the post, in seconds or minutes. 
The estimate is automatic; a custom value for a single post can be inserted using a Custom Field named “readingtime”.
For more info: https://www.whiletrue.it/reading-time-for-wordpress/

Reading Time

Reading Time shows the estimated reading time and puts an animated progress bar inside the post.

Postats vs Reading Time